Vault Construction Research Articles

Radiation Oncology-External-Beam Radiation Therapy.

The application of structural shielding design techniques and goals as outlined in the National Council on Radiation Protection and Measurements Report 151, Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities (2005), continues to be the basis for treatment vault design in 2018 with some updated information. Treatment techniques have changed significantly with the dominant usage of intensity-modulated radiation therapy techniques today based on concurrent imaging. Some of the developments in linear accelerator technology over the past 15 y include flattening filter-free modes, which enable higher instantaneous dose rates; three-dimensional conformal radiation therapy resulting in potentially higher workloads since healthy tissue is spared; improved intensity-modulated radiation therapy treatment delivery systems with lower monitor units per centigray delivered than traditional step and shoot intensity-modulated radiation therapy; stereotactic body radiation therapy with higher treatment fractions and increased workloads; and increased use of stereotactic radiosurgery with conventional linear accelerators as well as robotic arm-mounted linear accelerators with higher treatment fractions. These new treatment units also incorporate multiple-energy x-ray beams (2 to 5 MV typical), which require a significant change in the specification of a workload to be used in each vault. As the equipment in radiation oncology departments has evolved to state-of-the-art modalities, the requirements for adequate radiation shielding for these modalities has become more rigorous. Architectural designs no longer depend on standard maze design rectangular rooms. Innovative layouts and utilization of multiple layers of shielding materials allow much greater flexibility in room designs. Maze-less rooms with direct-shielded doors are part of these challenging designs and are very common today. Use of multiple-density concrete blocks allows quicker construction of vaults and requires less space for the equivalent shielding provided. Combinations of high-density or normal-density concrete, steel, and lead are used in designs to make optimum use of available space and cost. Additional shielding needed at the edges of these single- or bi-parting sliding doors as well as baffle designs for heating, ventilation, and air conditioning systems and communication cable penetrations require detailed calculations. Examples of these designs will be given in this presentation. Consideration of the radiation levels around the planned vault must also include adjacent multistory buildings.

El legado de Félix Candela en Colombia a través de seis proyectos inéditos

Este articulo explica los seis proyectos que el arquitecto Felix Candela, a traves de su empresa Cubiertas Ala, realizo en la ciudad de Cali (Colombia), entre 1958 y 1961, asociado con arquitectos locales. La primera parte presenta los antecedentes colombianos en la construccion de bovedas de membrana ejecutadas principalmente en ceramica armada. La segunda parte explica la manera en que Candela entro en contacto con arquitectos e ingenieros colombianos y describe detalladamente los seis proyectos que son objeto central del articulo a partir de sus caracteristicas tipologicas y constructivas. Por ultimo, se da cuenta de la influencia que estos disenos ejercieron en la tradicion local, promoviendo un uso mas generalizado del hormigon armado e impulsando una busqueda formal en el campo de las estructuras laminares adaptables a las condiciones del lugar.Palabras clave: estructura laminar, paraboloide hiperbolico, hormigon armado, estructura ligera.

La Casa Pizano y la bóveda ligera en Colombia. El origen de una tradición moderna

La Casa Pizano y la bóveda ligera en Colombia. El origen de una tradición moderna

HR LOD based HBIM to detect influences on geometry and shape by stereotomic construction techniques of brick vaults

The use of construction techniques in cloister vaults in noble buildings, as covering elements for square or rectangular rooms, is widespread across Europe. The geometric continuity at the intrados makes generally possible the execution all over the span of frescoes, stucco and decorations, with a great diffusion of a great variety of solutions. The construction of brick vaults, from the late Middle Age, was sped up by limiting the centring to the wooden planks arches that were instrumental in the profile determination. Starting from laser scanning, photogrammetric and thermographic techniques, the punctual reconstruction of the geometry and construction techniques allowed to recognise and understand the constructive richness, the multiplicity and unicity of each vaulted element, made of recurrent elements and specific features, thus sketching a mixed pattern of workers and highlighting the constructive knowledge of ‘stereotomy’ applied to the brick block vaults. Nowadays, the availability of several BIM-based modelling procedures and tools based on high detailed surveys allows to identify and reconstruct the shape, drawing reliable assumptions about the construction methods and the execution time. The research methodology here proposed intends to tackle an updatable geographic catalogue, able to transfer the construction richness, inheriting the historic lesson of French ‘repertoires’ to generate modern HBIM vault libraries (abaci). The paper focuses on a well-documented case, the Magio Grasselli palace in Cremona in which the cloister vaults of two main rooms, and others, show different construction systems embodied by the geometry. The methodology has shown how the cloister vault typology can be turned to a dome construction in the same vault, and how ‘stereotomy’, the capacity of skilled workers to control the space, modified the typical geometry, made by the ‘generative’ construction process used for the cloister vault (intended as the intersection of 2 barrel vaults), turning it into a dome in the upper part, giving back a sort of morphing, merging the two different generative rules (dome and vault) as described hereafter and creating unexpected scenic effect.

Multiply information coding and hiding using fuzzy vault

In this paper we show some new ideas of hiding several secrets with the use of fuzzy vault construction and, in addition, a few systems based on presented concept. The main assumption is that all pieces of information are put into single vault and each of the secrets is linked with individual key. The keys are required to be disjunctive, and each of them should be in form of unordered set. In recovering process, revealed information is dependent on used key. Presented method is error-tolerant and thus is suitable for working together with biometrics. The interesting characteristic of multi-secret fuzzy vault is that the adversary is not able to distinguish it from the single-secret version. The article describes also a number of information systems built on the basis of presented scheme, including cooperation with false steganography (where every biometric trait encodes different steganographic key), password management and multi-user systems.

Creativity in Three Dimensions: An Investigation of the Presbytery Aisles of Wells Cathedral

This paper explores the topics of creativity and imagination in relation to the design and construction of the lierne vaults in the presbytery aisles of Wells Cathedral, erected around 1330. It explores the potential of digital scanning and analysis for forensic investigation of the structure in order to identify the processes involved. Four different processes were employed and we compare those used in the three eastern bays of the north and south aisles. These are shown to share characteristics with the retrochoir but to involve different approaches to 3-D projection and stone-cutting. We conclude that the basic geometry of the vaults was defined in advance of construction, using full-scale drawings worked out on a tracing floor. In both sets of vaults the 3-D geometry continued as a sequence of steps and was derived from measurements ascertained from existing elements (including the drawings) but was not consistent across the two aisles. The processes reveal different priorities, whether for level ridges (north aisle), different choices in terms of rib radii or apex heights, and different sequences of design steps. This demonstrates the potential for experimentation at every stage of construction.

SHAPE AND CONSTRUCTION OF BRICK VAULTS. CRITERIA, METHODS AND TOOLS FOR A POSSIBLE CATALOGUE

Abstract. The use of cloister vaults in the construction of noble buildings, as covering elements for square or rectangular rooms, is widespread and well-known. The geometric continuity at the intrados makes generally possible the execution all over the span of frescoes, stucco and decorations. The construction of brick vaults, from the late Middle Age, was sped up by limiting the centering to the wooden planks arches that were instrumental in the profile determination. Nowadays, the availability of several procedures, phases and tools for carrying out a survey allows to draw reliable assumptions about the construction methods and the execution time. It is mandatory to determine the properties of the binders, the shape and dimensions of the bricks, and to carry out a comparison between the geometry of the intrados surface and the evidences emerging at the extrados. The support of the laser scanner technique allows to accurately identify the surface profile and thickness. All these indications, in turn, are useful, in view of an interpretation of the structural behavior, to identify weaknesses, and to highlight contributing factors of instability (if any). The paper focuses on a well-documented case, the Magio Grasselli palace in Cremona in which the cloister vaults of two main rooms show different construction systems, although they were built almost at the same time. The thermographic recordings and laser-scanner surveys highlight the various arrangements used for the cloister vaults.

Un apunte a la problemática constructiva de la Catedral de México: el caso de las cubiertas abovedadas y su replanteo hacia 1628

In 1628 archbishop Francisco de Manso y Zuniga, proposed the construction of vaults for the unfinished Mexico City Cathedral. He counted on the experience of the architect Juan Gomez de Trasmonte, who proposed a system of barrel vaults with lunettes for the central nave and sail vaults for the side aisles. Moreover, Gomez proposed three possible technical solutions for the use of different stone types: chiluca, los Remedios and tezontle. The following year serious flooding and its consequences delayed the execution of these works, but the 1628 plans would seem to be at the origin of the vaults extant today in the three naves of the Cathedral.

The Borbone “Istruzioni per Gli Ingegnieri”: A Historical Code for Earthquake-Resistant Constructions

ABSTRACTThe paper examines the instructions (Istruzioni and Suggerimenti) issued by order of Ferdinando IV of Borbone, King of Naples, in 1783 soon after the terrible earthquake that hit the Calabria Ulteriore region. The tremor had disastrous consequences on the morphology of the territory and on the local economy also making 30.000 human victims. The code was drawn by the two supervisors of the public works in the Calabria region, La Vega and Winspeare. It touches several points of building policy such as hygienic precautions, city planning, measures of civil protection and administrative rules for the distribution of soils for the reconstruction of the ruined estates. The very interesting point is that the document contains updated indications for the best practice of building in a zone with high seismicity, based on the most advanced theories of the time in the field of earthquake-resistant constructions. The document suggests to keep low the height of the new buildings, forbids the construction of vaults and prescribes the construction of a timber frame to be built into the masonry walls with the aim of connecting the various walls of the building and achieve a box behaviour of the whole construction. Furthermore, indications deal with the best practice for increasing the durability of the internal timber frame.

Сводчатые конструкции в домонгольской архитектуре Новгорода

Сводчатые конструкции в домонгольской архитектуре Новгорода

SU‐E‐T‐243: Design of a Novel Testing Port for Radiation Protection and Shielding Measurements

Purpose:The majority of radiation shielding research utilizes Monte Carlo simulation because of the difficulty in eliminating secondary radiations from measurements. We have designed a test port into a primary barrier of our newest vault to allow for shielding measurements while ensuring adequate protection to the public and staff during normal machine operation. This port allows for measurement of attenuation values of shielding materials, differential dose albedos, and radiation scatter fractions.Methods:The vault design utilized the maze as part of a compound primary barrier. The test port is contained within the maze and is centered along isocenter. The inner 30 cm has a 20×20 cm2 opening, while the remaining length has a 30×30 cm2 opening. The block that contains the port has a density of 200 pcf to minimize internal scatter. The 30×30 cm2 opening is occupied by removable 215 pcf concrete blocks. The innermost and outermost blocks activate an interlock wired into the beam‐enable loop. This disallows beam‐on in treatment mode if the interlock isn't closed. The interlock can be overridden in service mode, or by‐passed via an override switch in case of circuit failure.Results:The test port was installed in August. The beam is disabled when the interlock is tripped. Measurements taken when the primary beam is not incident on the port are indistinguishable from background. Ambient dose levels surrounding the vault with the designed shielding blocks in place are all within allowable limits for occupational workers.Conclusions:We have designed and installed a unique testing port for radiation protection and shielding measurements. This port is appropriately interlocked and designed to mitigate any risks of incidental exposure to staff or members of the public. The test port design allows measurements with “good geometry” and efficient removal of contaminating sources of radiation present in many shielding measurements.Daniel Harrell and Jim Noller are employees of Shielding Construction Solutions, Inc, the shielding construction company that built the vault discussed in this abstract. Manjit Chopra is an employee of Universal Minerals International, Inc, the company that provided the aggregates for the high density concretes used in the vault construction.

SU-E-T-271: Direct Measurement of Tenth Value Layer Thicknesses for High Density Concretes with a Clinical Machine

Purpose: Use of high density concrete for radiation shielding is increasing, trading cost for space savings associated with the reduced tenth value layer (TVL). Precise information on the attenuation properties of high-density concretes is not readily present in the literature. A simple approximation is to scale the TVLs from NCRP 151 according relative increase in density. Here we present measured TVLs for heavy concretes of various densities using a built-in shielding test port. Methods: Concrete densities tested range from 2.35 g cc−1 (147 pcf) to 5.6 g cc−1 (350 pcf). Measurements were taken using 6MV, 6FFF, and 10FFF on a Varian Truebeam linear accelerator. Field sizes of 4x4, 9x9 and 30x30 cm2 were measured. A PTW 31013 Farmer chamber with a buildup cap was positioned 5.5 m from isocenter along the beam CAX. Concrete thicknesses were incremented in 5 cm intervals. Comparison TVLs were determined by scaling the NCRP 151 TVLs by the density ratio between the sample and standard density. Results: The trend from the first to equilibrium TVL was an increase in thickness, compared with MC modeling, which predicted a decrease. Measured TVLs for 6 MV were reduced by as much as 8.9 cm for TVL₁ and 3.4 cm for TVLE compared to values scaled from NCRP 151. There was 1–3 mm difference in TVL between measurements done at 4x4 versus 30x30 cm2. TVL₁ for 6FFF was 1.1 cm smaller than TVL₁ for 6MV, but TVLE was consistent to within 4 mm. TVL₁ and TVLE for 10FFF were reduced by 8.8 and 3.7 cm from scaled NCRP values, respectively. Conclusions: We have measured the TVL thicknesses for various concretes. Simple density scaling of the values in NCRP 151 is a conservatively safe approximation, but actual TVLs may be reduced enough to eliminate some of the expense of installation. Daniel Harrell and Jim Noller are employees of Shielding Construction Solutions, Inc, the shielding construction company that built the vault discussed in this abstract. Manjit Chopra is an employee of Universal Minerals International, Inc, the company that provided the aggregates for the high density concretes used in the vault construction.

Geometry, Construction and Structural Analysis of the Crossed-Arch Vault of the Chapel of Villaviciosa, in the Mosque of Córdoba

ABSTRACTThe vault of Villaviciosa is one of the oldest existing examples of a true ribbed vault, and is the first of the crossed-arch type. Although its perfection suggests earlier trials, none has been found so far. It predates the oldest Romanesque ribbed vaults by more than a century. Notwithstanding its importance, no construction and structural study has ever been done; neither has an accurate survey been published. The purpose of this article is to fill this gap in the history of vault construction. A detailed survey has been made, providing the first accurate drawings of the vault. A close inspection of the extrados, completed with a visual inspection of interior damages, has allowed ascertaining the main construction features. With the geometry and the material data a structural analysis has been carried out. This analysis explains the fundamental structural behavior of the vault and throws new light into some historical issues; for example, it leads to discarding the widespread belief that the ribs are decorative: they are supporting the weight of the vault.

Islamic Architecture and Arch

The arch, an essential architectural element since the early civilizations, permitted the construction of lighter walls and vaults, often covering a large span. Visually it was an important decorative feature that was trans-mitted from architectural decoration to other forms of art worldwide. In early Islamic period, Muslims were receiving from many civilizations, which they improved and re-introduced to bring about the Renaissance. Arches appeared in Mesopotamia, Indus, Egyptian, Babylonian, Greek and Assyrian civilizations; but the Romans applied the technique to a wide range of structures. The Muslims mastered the use and design of the arch, employed for structural and functional purposes, progressively meeting decorative and symbolic pur-poses. Islamic architecture is characterized by arches employed in all types of buildings; most common uses being in arcades. This paper discusses the process of assimilation and charts how they contributed to other civilizations.

Isidore’s Compass

In the history of architecture, the construction of vaults was one of Rome’s supreme achievements, yet paradoxically it is not mentioned in any of the existing literary sources. Hero of Alexandria wrote a treatise entitled On Vaulting, which unfortunately is lost. A commentary on it was written by Isidore of Miletus, who lived at the time of the construction of the Hagia Sophia in Constantinople. We know this only from a brief remark in Commentary on the Sphere and Cylinder of Archimedes, written by Eutocius of Ascalon; furthermore the scholium refers to the drawing of a parabola. It was at about this same time that the parabola became very important in the East, as can be seen in the construction of Kosrow’s Arch at Ctesiphon. The present study examines Eutocius’ remark and the context in which it is to be found in his Commentary, and takes a look at the primacy of the parabola in the static behaviour of domes.

SU-E-P-16: The First TrueBeam System Commissioning Experience in Latin America

Purpose: To show the experience and results of the first TrueBeam™ linac in Latin America. Methods: Several data were analyzed and compared among installation, manufacturer and own measurements. It was necessary to define a base line for our own Quality Assurance program. Some comparisons were made with others TrueBeam users in order to be placed based on our quality and confidence level. Results: We show the complete process since vault construction until first patient treatment. The process is complex and full of information that will be shown at the meeting. Conclusion: This experience is unique now in our region so it is important to share the experience as a developer country and exchange trouble shooting with medical physics community around the world.

Ambient Noise Levels in Greece as Recorded at the Hellenic Unified Seismic Network

Abstract We investigate the characteristics of ambient noise across Greece as recorded at the Hellenic Unified Seismic Network (HUSN). Power spectral densities (PSDs) and their corresponding probability density functions (PDFs) have been estimated for 110 broadband seismic stations using the continuous waveform data for a four‐year period from 2007 to 2010. Using PDFs we monitor and show network performance in terms of overall station quality and the level of noise at each site. At high frequencies (>7 Hz), the main source of noise is cultural with strong diurnal variations. Stations with constantly increased noise levels across this band indicate poor vault construction or poor site selection and provide an indication to the network operators for possible structural improvements or even station relocations. The microseismic noise levels show a clear seasonal variation at all stations. Specifically, for the double‐frequency (DF; period range 4–8 s) band, the average noise level differs between stations on the mainland and those located on the islands, reaching a value as high as 10 dB. Furthermore, the DF noise peak is observed at all of the HUSN stations, and it is correlated well with local sea wave height measurements at buoys deployed in the Aegean and the Ionian seas. This indicates that the HUSN seismic network also monitors local sea–weather conditions within a range of a few hundred kilometers. The longer period single‐frequency (SF) band is affected by sea–weather conditions at much longer distances in the North Atlantic. Finally, we calculate the HUSN mode noise model (HMLNM) that represents the highest probability ambient noise level in Greece. This model is a realistic noise threshold for future seismic station installations. Online Material: Table of seismic sensor description, and tables, figures, and movie describing microseismic noise measurements.

Very broadband seismic background noise analysis of permanent good vaulted seismic stations

This paper describes the results of a preliminary study conducted to analyze seismic background noise at sites of recently deployed very broadband stations of the Egyptian National Seismological Network (ENSN). The main purpose of the study is to assess the effects of permanent seismic vault construction and also to establish characteristics and origin of seismic noise at those sites. Another goal of this study is to determine the time needed for noise at those sites to stabilize. The power spectral densities of background noise at short period band (SP), very broadband (VBB), and ultra long period band (ULP) for each component of each broadband seismometer deployed in the different investigated sites are calculated. A MATLAB code has been developed that manages data processing and data analysis and compares the results with the high-noise model (NHNM) and low-noise model (NLNM) of Peterson (1993). Based on the obtained analysis, the noise stability and the efficiency of each station to record regional and teleseismic events are measured. The results of this study could be used in the future to evaluate station quality, to improve those processes that require background noise values, such as automatic association, and to improve the estimation of station and network detection and location thresholds.

The Presbytery Vault at St Albans

The presbytery vault at St Albans is one of only two thirteenth-century wooden vaults over a main span to survive in England. A programme of cleaning and conservation carried out between 1997 and 2002, coupled with an analysis of the source and date of the timber used in its construction, significantly advanced our understanding of both the late thirteenth-century presbytery campaign at St Albans and thirteenth-century timber vault construction generally. As the inevitable density and restricted circulation of the final report on that work has hindered its wider reception, the following paper offers a summary, drawing attention to two features that may have wider implications for an appreciation of vaulting in timber. The first is that, although the general form adopted at St Albans is one associated with masonry vaulting, the wooden boards used for the vault webbing required a junction between the wall and the ridge rib, meaning that shallow liernes were originally deployed to run parallel to the central ridge. It is difficult to see this as imitative of vaulting in stone; rather it is likely to be the result of carpenters developing their own solutions to the constraints imposed by timber. Secondly, the late medieval remodelling of the vault replaced these liernes with false tiercerons, and rather nicely illustrates the ease with which timber vaulting could be modified. The dendrochronology gives a date range of 1273–93, and a date of around 1285 is suggested for the primary build. The major late medieval alterations are here associated with the second abbacy of John of Wheathampstead (1452–65).

Tile vault architecture and construction around Eduardo Sacriste

Around the architect Eduardo Sacriste (1905-1999), a noted scholar of vault architecture and construction, a prolific generation of architects emerged in Argentina in the middle decades of the twentieth century. Many of them designed buildings covered with tile vaults, or, in some cases, with different variations on this system. Most of the experiences they carried out are collected in Viviendas con bovedas , a detailed study directed by Sacriste in the late 70s. The interest of these buildings lies both in the use of classic tile vaulting and the evolution of this system to new variants, some of great interest. Most of these variants, which were designed at the time for a particular area, have transcended, however, its local condition: the legacy of Sacriste’s generation is clear, at present, not only in some recent attempts to recuperate tile construction, but in numerous international projects of lightweight vault construction.